KR100257607B1 - Projection type image display apparatus - Google Patents

Abstract

PURPOSE: An image display device is to reduce light loss and increase brightness of screen by using two AMA(actuated mirror array) panels and to reduce production cost. CONSTITUTION: Beam is generated from a light source(111). A projection lens(116) projects an image on a screen. The first AMA panel(120) and the second AMA panel(122) comprise pixels of mirrors for reflecting beam, each mirror being deformed to a size corresponding to a strength of its corresponding one pixel. A beam generated from the light source has three primary colors consisting the fist, the second and the third color beam and is divided into the first color beam and the fourth color beam made by combining the second and the third color beam. The first color beam is irradiated to the first AMA panel while the fourth color beam is irradiated to the second AMA panel. A micro color filter array(140) comprises the first micro color filter and the second micro color filter arranged in the same pitch as that between the mirror pixels of the second AMA panel.

Description

Projection type image display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type image display device, and more particularly to a projection type image display device including an Actuated Mirror Array (AMA) panel used for projecting an image onto a screen. A projection type image display apparatus capable of displaying color images using a panel.

In general, spatial light modulators, which are devices for projecting optical energy onto a screen, can be applied to various fields such as optical communication, image processing, and information display devices. Typically, such devices are classified into a direct-view image display device and a projection-type image display device according to a method of displaying optical energy on a screen.

An example of a direct-view image display device is a CRT (Cathode Ray Tube). The CRT device is called a CRT, which has excellent image quality but increases in weight and volume as the screen is enlarged, leading to an increase in manufacturing cost. There is.

Examples of the projection image display apparatus include a liquid crystal display (LCD), a deformable mirror device (DMD), and an actuated mirror array (AMA). Such projection image display devices can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmissive spatial light modulators, while DMD and AMA can be classified as reflective spatial light modulators.

Transmission optical modulators, such as LCDs, have a very simple optical structure, which makes them thinner, lighter in weight, and smaller in volume. However, due to the polarity of the light, the light efficiency is low, there is a problem inherent in the liquid crystal material, for example, there is a disadvantage that the response speed is slow and the inside is easy to overheat. In addition, the maximum light efficiency of existing transmission light modulators is limited to a range of 1-2%, requiring dark room conditions to provide acceptable display quality.

Optical modulators such as DMD and AMA have been developed to solve the problems of the aforementioned LCD type optical modulators. DMD shows a relatively good light efficiency of about 5%, but serious fatigue problems are caused by the hinge structure employed in the DMD. In addition, there is a disadvantage that a very complicated and expensive driving circuit is required.

In the AMA, each of the mirrors installed therein reflects light incident from the light source at a predetermined angle, and the reflected light is projected on the screen through an aperture such as a slit or a pinhole. It is a device that can adjust the speed of light to form an image. Therefore, its structure and operation principle are simple, and high light efficiency (more than 10% light efficiency) can be obtained compared to LCD or DMD. In addition, the contrast of the image projected on the screen is improved to obtain a brighter and clearer image.

Each actuator of the AMA generates a deformation in accordance with the electric field generated by the applied electric picture signal and the bias signal. As the actuator deforms, each of the mirrors mounted thereon is tilted. Accordingly, the inclined mirrors reflect light incident from the light source at a predetermined angle to form an image on the screen. Piezoelectric materials such as PZT (Pb (Zr, Ti) O ₃ ) or PLZT ((Pb, La) (Zr, Ti) O ₃ ) are used as actuators for driving the respective mirrors. The actuator may also be configured as a warping material such as PMN (Pb (Mg, Nb) O ₃ ).

These AMAs are largely divided into bulk type and thin film type. Bulk AMA is disclosed in US Pat. No. 5,085,497 to Gregory Um et al. The bulk AMA is made by thinly cutting a multilayer ceramic to mount a ceramic wafer having a metal electrode formed therein in an active matrix in which a transistor is built, and then processing by a sawing method and installing a mirror thereon. However, bulk AMA requires very high precision in design and manufacture, and has a disadvantage of slow response of the strained layer. Accordingly, recently, a thin film type AMA that can be manufactured using a semiconductor manufacturing process has been developed. For example, such a thin film type AMA is disclosed in Korean Patent Application No. 95-13353 filed by the applicant of the Korean Patent Office.

Thin film type AMA (TFAMA) is a reflective light modulator that uses thin film piezoelectric actuators in conjunction with microscopic mirrors. It has been developed to have a degree. This TFAMA consists of panels of 640x480 pixels representing red (R), green (G) and blue (B), respectively. The pixels are designed as cantilever structures to maximize the mirror surface area to increase the light efficiency. The cantilever structure includes an active matrix to which an image signal is applied and a mirror operated by the applied signal.

FIG. 1 illustrates a conventional projection type image display device that can display a color image corresponding to the colored light by sequentially projecting red, green, and blue light rays on a screen using a single-plate thin film type AMA. It is.

In order to display a color image on the screen, three rays of red, green and blue must be modulated by a spatial light modulator, such as an AMA. In particular, in projection systems using single-plate light modulators, these light modulators are sequentially There is a need for means for irradiating green and blue lights.

Referring to FIG. 1, a conventional projection type image display apparatus 10 includes 170W to 250W metal halide lamps 11 for emitting light rays, and light rays emitted from the lamps 11 as parallel light. A source stop 12 for making an image, a color wheel 15, an aperture for passing the light beam, a source stop 13 for determining the amount of light forming the image, and a source stop 13 Source mirror 14 for primarily changing the path of the light beams passing through), field lens 16 for mapping the image of the source stop 13 to the projection stop 20 at 1: 1, and a plurality of An AMA panel 18 having a mirror and adapted to modulate the intensity of the light emitted from the field lens 16, a projection stop 20 having an opening for passing the light and concentrating the flux of the modulated light; And the projection stop 20 And a projection lens 22 for projecting the passed light rays onto a screen (not shown).

2 is an enlarged view of the color wheel 15. As shown in FIG. 2, the color wheel 15 consists of a series of color segments of red, green and blue transmission filters and is adapted to the white light while rotating about its axis by a drive such as a motor. Change the color

The operation principle of the conventional single-plate projection type image display apparatus 10 having the above structure will be described with reference to FIGS. 1 and 2 as follows.

The light rays emitted from the lamp 11 are condensed into parallel light by the source lens 12 and then focused toward the color wheel 15. The color wheel 15 rotates about its axis such that its color segments sequentially block white light. Accordingly, after the white light passes through the color wheel 15, it sequentially changes into red, green, and blue color light rays, which pass through the opening of the source stop 13 to the source mirror 14. The light path is irradiated, and the light path is primarily changed and then incident on the field lens 16. Red, green, and blue light rays sequentially passing through the field lens 16 are sequentially irradiated to the AMA panel 18 with parallel light. The mirror of the AMA panel 18 modulates the light beams in accordance with a signal applied to an actuator provided thereunder. As a result, the red, green and blue light rays reflected from the mirror of the AMA panel 18 are focused on the field lens 16 and then irradiated onto the projection stop 20.

The color light rays passing through the opening of the projection stop 20 are projected onto the screen by the projection lens 22 to display a color image corresponding thereto. For example, when red light is irradiated onto the AMA panel 18, the AMA panel 18 forms an image corresponding to red and projects it on the screen. Then, the green image by green light and the blue image by blue light are sequentially displayed on the screen. However, with the naked eye, the monochrome images of each of the red, green, and blue colors are combined and recognized as full color.

According to the conventional single-plate projection type image display apparatus described above, white light is sequentially changed into red, green, and blue light using a color wheel. The color wheel is rotated about its axis so that three color segments (i.e. red, green and blue segments) each occupying one third of the area are sequentially blocked white light, so that the total white light emitted from the lamp 2/3 of it is always lost. In addition, when white light is irradiated to the boundary areas of the color fragments of the color wheel, there is a problem in that the contrast of the image of the screen is lowered because the light rays of the color that come out of the two areas are not emitted.

FIG. 3 shows a projection image display apparatus capable of displaying a color image using a three panel AMA to solve the problem of light loss described above.

Referring to FIG. 3, the conventional three-plate projection image display device 50 includes a 170W to 250W halogen metal lamp 51 for emitting light rays, and a source lens 52 for condensing the light rays emitted from the lamp 51. ), A source stop 53 having an opening for passing the light beam and determining an amount of light beam forming an image, and a source mirror 54 for primarily changing the path of the light beam passing through the source stop 53. Two dichroic filters (57, 58) for selectively passing light by wavelength, and three (1) to match the image of the source stop (53) to the projection stop (55). Three AMA panels 70, 72, and 74 consisting of an array of mirror pixels and three field lenses 60, 62, and 64 for modulating the intensity of light emitted from the field lenses 60, 62, and 64; Said opening having an opening for passing light rays A projection stop for concentrating the flux of the beam 55, and includes a projection lens 56 for projecting a light beam passing through the stop projection (55) on a screen (not shown).

The operation principle of the conventional three-plate projection image display device 50 having the above-described structure will be described with reference to FIG. 3 as follows.

Light rays generated from the halogen metal lamp 51 are focused on the source lens 52 and then irradiated onto the source mirror 54 through the opening of the source stop 53. The light rays irradiated on the source mirror 54 are entirely reflected and irradiated onto the first dichroic filter 57.

Since the first dichroic filter 57 transmits green and blue light and reflects red light, the reflected red light is irradiated to the R-AMA 70 through the R-field lens 60. The mirror of the R-AMA 70 modulates the light beam according to a signal applied to an actuator provided thereunder. As a result, the red light modulated by the R-AMA 70 is irradiated back to the first dichroic filter 57 through the R-field lens 60, and then reflected by it to reflect the projection stop 55. Headed. The red light passing through the opening of the projection stop 55 enters the projection lens 56.

On the other hand, the green light and blue light transmitted through the first dichroic filter 57 are reflected by the second dichroic filter 58 and the green light is transmitted. The blue light reflected by the second dichroic filter 58 is irradiated to the B-AMA 72 through the B-field lens 62. The mirror of the B-AMA 72 modulates a light beam in accordance with a signal applied to an actuator provided thereunder. As a result, the blue light modulated by the B-AMA 72 is irradiated back to the second dichroic filter 58 through the B-field lens 62, and is reflected by the first dichroic filter ( 57). Since the first dichroic filter 57 transmits blue light as it is, the transmitted blue light passes through the opening of the projection stop 55 and then enters the projection lens 56.

Green light transmitted through the second dichroic filter 58 is irradiated to the G-AMA 74 through the G-field lens 64. The mirror of the G-AMA 74 modulates the light beam according to a signal applied to an actuator provided thereunder. As a result, the green light modulated by the G-AMA 74 is irradiated to the second dichroic filter 58 again through the G-field lens 64, and the second dichroic filter 58 is turned on. It is transmitted and irradiated to the first dichroic filter 57. Since the first dichroic filter 57 transmits green light as it is, the transmitted green light passes through the opening of the projection stop 55 and then enters the projection lens 56.

In this way, the projection lens 56 projects a color ray including three rays of red, green and blue on the screen to display a color image corresponding thereto.

According to the conventional three-panel projection type image display device 50 described above, light loss can be reduced as compared to a single-plate device using a color wheel, but three AMA panels are used, so that the manufacturing cost is high and the size of the optical system is increased. There is a disadvantage.

Accordingly, an object of the present invention is to provide a projection type image display device including an AMA panel, which can improve the brightness of a screen compared to a single plate type device and reduce manufacturing costs compared to a three-plate type device. .

1 is a schematic diagram showing a conventional single-plate projection image display device.

FIG. 2 is an enlarged view of a color wheel used in FIG. 1.

3 is a schematic diagram showing a conventional three-plate projection image display device.

4 is a schematic diagram showing a projection image display device according to the present invention.

FIG. 5 is a plan view of the micro color filter array shown in FIG. 4.

<Explanation of symbols for main parts of the drawings>

100: projection image display device 111: lamp

112: source lens 113: source stop

114: source mirror 115: projection stop

116 projection lens 118 color separation means

120, 122: AMA panel 130, 132: field lens

140: micro color filter array

The present invention to achieve the above object, a light source for generating a light ray; A projection lens for projecting an image onto a screen, pixels of a mirror for reflecting light rays, each mirror having a deformation size corresponding to the intensity of a corresponding one of a plurality of pixels displayed on the screen. The first and second AMA panels to be deformed, and the light rays generated from the light source are combined with the first color light ray and the second color light ray and the third color light ray among three primary colors of light including the first, second and third color light rays. Color separation means for irradiating the first color light beam to the first AMA panel by dividing it into a fourth color light beam and irradiating the fourth color light beam to the second AMA panel, and a pitch between mirror pixels of the second AMA panel And micro color filters arranged at the same pitch, and dividing the fourth color light beam into a second color light beam and a third color light beam to irradiate each mirror pixel of the second AMA panel. To It provides a projection type image display device comprising a micro color filter array.

As described above, according to the projection type image display device according to the present invention, by displaying a color image using two AMA panels, it is possible to reduce the light loss compared to the single-plate type device using a conventional color wheel, thereby improving the brightness of the screen In addition, the number of optical components can be reduced compared to the conventional three-plate device, thereby reducing the manufacturing cost.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 4 is a schematic diagram showing a projection image display device including a two-plate thin film type AMA panel according to the present invention.

Referring to FIG. 4, the projection image display apparatus 100 according to the present invention includes a light source 111 for emitting light rays, a source lens 112, a source stop 113, a source mirror 114, and a projection stop 115. ), Projection lens 116, color separation means 118, first and second AMA panels 120 and 122, first and second field lenses 130 and 132, and micro color filter array 140 Include.

The light source 111 for emitting light rays preferably emits long wavelength infrared (LWIR) to ultraviolet (UV) light in the spectrum as a halogen metal lamp of 170W to 250W. The source lens 112 collects light rays emitted from the lamp 111. The source stop 113 is an optically opaque member and has an opening formed to allow light to pass therethrough. The source stop 113 determines the amount of light that forms the image. The source mirror 114 serves to reflect the light rays passing through the source stop 113 to change its light path to the color separation means 118.

The color separating means 118 is preferably one dichroic mirror, wherein the first color light ray and the first color light ray are selected from among three primary colors of light consisting of a first color light ray, a second color light ray and a third color light ray. It serves to separate the dichroic rays and the third color rays into the combined fourth color rays. The dichroic mirror 118 is a reflector composed of many thin layers of materials having different refractive indices. The dichroic mirror 118 reflects light of a certain color and transmits all light of a different color. According to a preferred embodiment of the present invention, the first color light is blue light (B), the second color light is red light (R), and the third color light is green light (G). Therefore, since the dichroic mirror 118 reflects the blue light B and transmits the red light R and the green light G, the light transmitted through the dichroic mirror 118 is yellow light in which the red light and the green light are combined. (R + G).

The first field lens 130 and the second field lens 132 pass through the source stop 113 so that the image of the source stop 113 corresponds to the projection stop 115 at 1: 1. It serves to irradiate the light rays of the first AMA panel 120 and the second AMA panel 122 corresponding thereto without light loss.

The micro color filter array 140 includes a first micro color filter 142a and a second micro color filter 142b arranged at the same pitch as the pitch between the mirror pixels of the second AMA panel 122. The fourth color light beam transmitted through the dichroic mirror 118 is separated into a second color light beam and a third color light beam to irradiate each mirror pixel of the second AMA panel 122.

5 is a plan view of the micro color filter array 140. Referring to FIG. 5, the micro color filter array 140 according to an exemplary embodiment of the present invention may include a first micro color filter 142a corresponding to red light R and a second micro color filter corresponding to green light B. FIG. 142b is repeatedly arranged. Therefore, the yellow light R + B incident on the micro color filter array 140 is separated into red light R and green light G and irradiated to each mirror pixel of the second AMA panel 122.

In addition, according to another preferred embodiment of the present invention, the first micro color filter 142a and the second micro color filter 142b may be arranged in a stripe shape.

The first AMA panel 120 and the second AMA panel 122 are composed of pixels of a mirror for reflecting the irradiated light beam, each mirror of which the intensity of the light beam according to the signal applied to the actuator formed thereon Modulate. That is, each mirror is deformed to a deformation size corresponding to the intensity of the corresponding one pixel among the plurality of pixels displayed on the screen. According to a preferred embodiment of the present invention, the first AMA panel 120 is irradiated with blue light (B) and the second AMA panel 122 and the red light (R) separated by the micro color filter array 140 and Green light G is irradiated.

The projection stop 115 is an optically opaque member, and has an optically reflective surface and an opening formed to pass a light beam. Preferably, the opening is a pinhole or slit. The flux of light rays passing through the opening of the projection stop 115 controls the intensity of light reflected from each mirror of the first AMA panel 120 and the second AMA panel 122.

The projection lens 116 serves to project the color light rays that pass through the opening of the projection stop 115 onto a screen (not shown).

Hereinafter, the operation principle of the projection image display apparatus 100 according to the present invention having the above-described structure will be described with reference to FIG. 4.

The light rays emitted from the halogen metal lamp 111 are collected by the source lens 112 and then irradiated to the source mirror 114 through the opening of the source stop 113. Light rays irradiated on the source mirror 114 are totally reflected and irradiated on the dichroic mirror 118. The dichroic mirror 118 reflects blue light (B) and transmits red light (R) and green light (G). The blue light B is irradiated to the first AMA panel 120 through the first field lens 130. The mirror of the first AMA panel 120 modulates the light beam according to a signal applied to an actuator provided thereunder. If an OFF voltage, that is, a voltage of zero (0) is applied to the actuator, the mirror of the first AMA panel 120 is not tilted and thus the blue light B causes the projection stop 115 to stop. Will not pass. However, when an ON voltage is applied to the actuator, the mirror of the first AMA panel 120 is tilted so that the intensity of the blue light B is modulated. As a result, the blue light B reflected by each mirror of the first AMA panel 120 is irradiated to the dichroic mirror 118 through the first field lens 130 and then reflected by it to stop projection. Head (115). The blue light B that has passed through the opening of the projection stop 115 enters the projection lens 116.

On the other hand, the red light and green light transmitted through the dichroic mirror 118 are combined and irradiated to the second field lens 132 with yellow light (R + G). The second field lens 132 turns yellow light into parallel light and irradiates the micro color filter array 140. As shown in FIG. 5, the micro color filter array 140 includes a first micro color filter 142a corresponding to the red light R and a second micro color filter 142b corresponding to the blue light B. As shown in FIG. Therefore, the red light R passing through the first micro color filter 142a is irradiated to the corresponding R-mirror pixel of the second AMA panel 122. When an OFF voltage is applied to an actuator corresponding to the R-mirror pixel of the second AMA panel 122, the R-mirror pixel is not tilted and thus the red light R causes the projection stop 115 to stop. Will not pass. However, when an ON voltage is applied to an actuator corresponding to the R-mirror pixel of the second AMA panel 122, the R-mirror pixel is tilted and the intensity of the red light R is modulated. As a result, the red light R reflected by the R-mirror pixel of the second AMA panel 122 is irradiated to the dichroic mirror 118 through the second field lens 132. Since the dichroic mirror 118 transmits the red light R as it is, the transmitted red light R passes through the opening of the projection stop 115 and then enters the projection lens 116.

Meanwhile, the green light G passing through the second micro color filter 142b is irradiated to the corresponding G-mirror pixel of the second AMA panel 122. When an OFF voltage is applied to an actuator corresponding to the G-mirror pixel of the second AMA panel 122, the G-mirror pixel is not tilted and thus the green light G causes the projection stop 115 to stop. Will not pass. However, when an ON voltage is applied to an actuator corresponding to the G-mirror pixel of the second AMA panel 122, the G-mirror pixel is tilted and the intensity of the green light G is modulated. As a result, the green light G reflected by the G-mirror pixel of the second AMA panel 122 is irradiated to the dichroic mirror 118 through the second field lens 132. Since the dichroic mirror 118 transmits the green light G as it is, the transmitted green light G passes through the opening of the projection stop 115 and then enters the projection lens 116.

In this way, the projection lens 116 projects a color ray including three rays of red, green and blue on the screen to display a color image corresponding thereto.

As described above, according to the projection-type image display device according to the present invention, by displaying the color image using the two AMA panels, it is possible to reduce the light loss compared to the single-plate type device using a conventional color wheel to improve the brightness of the screen In addition, the number of optical components can be reduced compared to the conventional three-plate device, thereby reducing the manufacturing cost.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (6)

A light source 111 for generating light rays; A projection lens 116 for projecting an image onto the screen; A first activated mirror array (AMA) consisting of pixels of a mirror for reflecting light rays, each mirror being deformed to a deformation size corresponding to the intensity of a corresponding one of a plurality of pixels displayed on the screen. ) Panel 120 and second actuated mirror array (AMA) panel 122; The first color light ray and the second color light ray and the third color light ray are combined among the three primary colors of light including the first light ray, the second color ray, and the third color ray. Color separating means (118) for irradiating the first color light beam to the first AMA panel (120) and irradiating the fourth color light beam to the second AMA panel (122) by separating into a fourth color light beam; And The first micro color filter 142a and the second micro color filter 142b are arranged at the same pitch as the pitch between the mirror pixels of the second AMA panel 122. And a micro color filter array (140) for irradiating each mirror pixel of the second AMA panel (122) by separating the color beams and the third color beams. The projection image display device according to claim 1, wherein the first color light is blue light and the fourth color light is yellow light in which red light and green light are combined. The micro color filter array 140 of claim 1, wherein the micro color filter array 140 includes the first micro color filter 142a corresponding to the first color light beam and the second micro color filter 142b corresponding to the second color light beam. Is repeatedly arranged. The projection type image display apparatus according to claim 1, wherein said color separation means (118) is one dichroic mirror. The method according to claim 1, wherein the first and fourth color light beams obtained from the color separation means 118 are converted into parallel light and corresponded to the first AMA panel 120 and the second AMA panel 122 corresponding thereto. And a first field lens (130) and a second field lens (132) for irradiation. 6. The projection image display device according to claim 5, wherein the micro color filter (140) is positioned between the second field lens (132) and the second AMA panel (122).

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